Dental device



May 21, 1940- c. D. MAsTRUD 2,201,190

DENTAL DEVICE Filed Jan. 5, 1939 Patented May 21, 1940 UNITED STATESPATENT OFFICE Conrad D. Mastrud, Chicago, Ill.

Application January 3, 1939, Serial No. 248,986

3 Claims.

This invention relates to improvements in dental devices.

One object of the invention is,l to provide power means for operating atoothbrush or like appli- 5 Gator or massaging device in relativelysmall paths in the plane of the portion of the gums or teeth beingtreated whereby the eifect of the treatment can be concentrateduniformly upon a denite part or parts of the gums or teeth withoutexcessive rubbing or abrading action which may tend to injure affectedtissues. In the treatment of many dental cases, l1v have found thatdelicate massage of the gums is of denite benefit, but that it is bestapplied by an applicator such as a brush moving in a very restrictedpath over the gums so as not to abradethe high points or ridges of thetissue surface and inadequately treat the low points or valleys betweenthe ridges. The amplitude of movement of the brush should be such thatwhen the flexible bristles'are placed against the gums the individualbristles will be restricted to substantially rotary paths close to thelongitudinal axis of the respective bristles and hence will not be drawnfrom the low points over the high points. By thus localizing the actionof the bristles, the gum surface including the tissue in the embrasurespaces between the teeth can be massaged uniformly by the sides of thebris`l tles without injuring the tissue of the high portions bysubstantial relative movement of the free ends of the bristles. 'Ihecapability of the improved deviceto massage or clean in Well definedlocalized areas by holding the operating member for a brush or the likerelatively stationary, enables the user easily to avoid treating a soreor tender spot in the gums while obtaining the benefit of the massagingaction on closely adjacent tissues.

Another object of the invention is to provide a brush operating memberto and from which brushes or similar massaging oreleaning means can bereadily attached or detached, the shanks or handles of which brushesextend axially from the operating member and are operated thereby andcooperate with the operating member to prevent the entrance of water,cleansing paste, or other foreign substance into the adjacent end of theoperating member and the mechanism carried thereby.

A further object of the invention is to provide an operating memberprovided with mechanism adapted to be actuated by an electric motor, forexample, which mechanism transmits power from the motor to a brush orthe like carried by the operating member, and translates the rotaryaction of the motor into circular or elliptical motion in the brushwhereby the free ends of the bristles move in rather minute paths in theplane of the bristle ends. i

Another object of the invention is to provide a 5 brush operating membercomprising a hand manipulatable casing which is light in weight and themechanism in which is adapted to be actuated by an electric motor via aflexible shaft, in which member is provided means to prevent ro- `10tation of the casing of the operating member by the exible shaft whenthe member is laid down with the motor running.

A further object of the invention is to provide a brush operating membercomprising a casing and' l5 a brush actuating arm extending exteriorlyof the casing and means cooperating with said member for guiding thesame and preventing entrance of foreign matter into the casing orpassage of lubricant therefrom. y

Other objects relate to various features of constructionand arrangementof parts which will be apparent from a consideration of the followingspecification and accompanying drawing where- Fig. 1 is a side elevationof a dental device embodying the present improvements;

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1;

Fig. 3 is a sectional view taken on line 3-4-3 of 30 Fig. 2;

Fig. 4 is a sectional view taken on line 4-4 of Fig. 2; j

, Fig. 5 is a section taken on line 5-5 of Fig. 2;

and

Fig. 6 is a section taken on line 6-6 of Fig. 2.

In Fig. 1 of the drawing, a handvmanipulatable casing l0 is shownprovided with mechanism4 therein for operating a massaging or cleaningdevice,rsuch as a toothbrush, indicated by numeral 40 I I. The mechanismwithin the casing I0 preferably is operable by means of a flexible shaftl2 comprising an outer nonrotatable sheath l2a and a driven shaft 12bWithin the latter which in turn is connected to an electric motor, notshown in 45 detail, but housed within a casing I3, the casing preferablybeing provided with a base I3a which supports the motor when the same isplaced upon a table or other horizontal support, and which may beprovided with an eye I3b by means of 50 which the motor may be supportedin thevertical position shown in Fig. 1 when desired. The casing Hl inthe form illustrated comprises two mat- .ing sections |0a and Illb`secured together by means of screws I4 or the like. Horizontally ds- 55posed within the casing is a shaft I 5 which is supported by a suitablebearing or journal I6. The rear end of the shaft I5a is tubular and ofsomewhat greater diameter than the remainder of the shaft. The tubularportion I5a is slotted as at |51) for the reception of a driving end I7which is secured to the forward end of the flexible shaft I2b. Themember I7 is provided with a pin I8 disposed diametrically thereof, theends of which are receivable in the slots |577 to provide a drivingcoupling connection between the drive shaft I2b and the shaft I5. Therear portion of the interior of the casing member Ilia, as shown in Fig.2, is provided with recesses or cavities I9 and 20 beneath which is abridging member 2I which forms one support for the bearing or journalIB.

Disposed approximately centrally of the casing IB is a bevel gear 22having teeth which mesh with the teeth of a pinion 23 mounted on theforward end of the shaft I5. The gear 22 is provided with a lower axialextension 22a which is journaled in a bearing member 24, and at theopposite side is provided with a co-axial shaft extension 25 which isjournaled in a bearing member 26 carried by the casing section Ilia.Beneath the journal or axial extension 25 is an eccentric or cam member27 which may be made as a portion of thegear or as a portion of theshaft comprising sections 22a and 25. The eccentricity of the member 27with respect to the axis of the shaft is quite small. For dentalpurposes, where brushes areemployed for providing the desired massagingand cleaning action, I have found that an eccentric off-set from theaxis of the shaft a distance of less than 1/20 ofv an inch issatisfactory, so that the maximum throwy of the eccentric or cam is lessthan le of an inch. The degree of eccentricity may be varied, but formassaging purposes I have found the above best suited for the purposesmentioned.

This eccentric member 27 determinesone diameter of the circular orelliptical path through which th'e bristles move during operation of"the device, and-hence, as stated above, an eccentric of small throw isdesirable( In the embodiment of the structure disclosed, a sleeve 28 iscarried by the eccentric 27 into which extend diametrically oppositestuds 23a. Upon the studs are pivotally mounted the extremities of armsof the yoke 29 which constitute the rear end of an operating armindicated generally by the numeral 33.' The arm`3IB` is disposed Withina longitudinal passage 3l formed in the forward portion of the casing,and has its extreme forward end disposed outwardly of the casing. Thisforward end, indicated by numeral 36a, preferably is provided withopposite convergent .nat sides 35h, while the upper and lower surfacesSc are rounded and also convergent. A catch is carried by the end 36a,which may be in the form of a pair of balls SIIC, portions of which arespring-pressed beyond the at surfaces 3073y for inter-engagement withina socket of a removable toothbrush or like applicator, as will bedescribedhereinafter.

The varm 3D is provided with a pivotal guide member within ,the passage3| at a point adjacent the forward end of the casing I. This `guidemember preferably is in the form of a ball 32 which seats in a sphericalrecess 33, one-half of which is formed in each of the casing sectionsIlia and Ilib. The ball is provided with a rearwardly projecting sleeve34 through which said arm extends. Surrounding the arm 3B, adjacent theforward end of the sphericalpivoting member 32, sealing means areprovided for preventd ing the entrance of foreign matter along the arminto the recess in the member 32, through which the arm projects. Thismember, which is indicated by the numeral 35, may be in the form of amolded washer of exible material such as sponge or other rubber, whichis retained in position by means of an annular ring 36 whichfrictionally seats over the forward reduced end of the casing I0.

In operation, the flexible shaft I2b effects rotation of theshaft I5,the pinion 23 on the end of which causes rotation of the gear Z2 and,likewise, of the eccentric or cam member 27. The rotation of theeccentric about the axis of the pinion produces rotary movement of therear end of the arm with the result that the arm not only moves to andfro or longitudinally within the recess 3|, but it has a pivotalmovement imparted thereto by the bearing 32, the bearing pivoting aboutan axis parallel with the axis of the gear 22 is viewed in Fig. 2. Theflexible sealing member 35 compresses and expands in response to thedescribed movement of the arm for maintaining a constant seal around thearm 34, and is retained against inward displacement by spherical bearing32 and against outward displacement by the flanged ring 3E during theoperation of the arm.

A brush, such as indicated by numeral II, flares outwardly toward itsrear end and preferably terminates in an annular flange 37 whichprevents water or paste from iiowing beyond the end of the brush shankand finding its way into the interior of the shank and possibly from thef latter along the arm into the mechanism Within the casing. While theflexible sealing member 35 is designed to prevent the entrance of suchmatter, the flange 30 is an additional safeguard against the admissionof cleansing powder or paste or such other matters as may cause thelubricant Within the casing from becoming fouled and hard, and therebyimpairing the operation of the mechanism.

The shank IIa of the toothbrush is provided with a socket IIb, the wallsof which are shaped in conformity with the walls 3th and 30o of the tangor forward end 30a of the arm 30. Small depressions 33 preferably areformed in opposite walls of the socket recess for receiving the prol,

jecting portions of the balls or catch members 30C for releasablyretaining the brush in position on the arm. As shown in Fig. 2, `therear extremity of the shank IIa is recessed as at 39 to accommodate theforward end of the casing I0 and in fact extends rearwardly of the saidforward end for the purpose of guarding against the passage of foreignmatter into contact with the forward end of the arm 30 from which it maypossibly work past the sealing member 35 and into the ball 32. Therecess 39 is of adequate length and diameter to accommodate the movementof the shank imparted thereto by the arm 3B during operation of thedevice.

The bristles 40 of the brush extend in a direction parallel with theaxis of the gear 22 whereby that is, the diameterY extendingltransversely with reference-,to the longitudinal axis of the casing Illis determined by the throw `of the eccentric in connection with therelative lengths of arm 30 between the pivot and brush and the pivot andyoke respectively. In the modification shown, the distance from thepivotal axis of the ball 32 to the bristles of the brush is somewhatgreater than the distance from the axis of the ball 32 to the axis ofthe gear 22. Hence, with such an arrangement, the paths of movement ofthe bristles will be slightly elliptical, the major diameters extendingtransversely of the brush. Hence when the brush is held against theteeth with `the handle horizontal, in the manner of an ordinarytoothbrush, and the device is set in operation, the bristles will move aslightly greater extent up or down, or longitudinally of the teeth, thanin a direction transversely of the teeth whereby the embrasure spacesbetween the teeth may more effectively be cleaned. It will be seen thatdue to the relatively small major and minor diameters of the paths ofmovement of the base ends of the bristles, that upon application of thebrush to the surface of the teeth and gums that the free ends of thebristles will remain stationary while the bodies of the bristles areswung around in a relatively small elliptical path with the brush back,whereby a localized area of the teeth or gums may be massaged or treatedby the sides rather than the free ends of the bristles while themanipulatable handle IU is held stationary. It is thus possible by theuse of this device to localize the treatment in relatively confinedareas of the gums and avoid application to infected or tender spots orportions where such is desirable. At the same time, the relatively smalldiameters of the paths of movement of the individual bristle endsenables the flexible bristles to be pressed against a definite area ofthe gums including high and low spots, and treat all portions of sucharea substantially uniformly without causing the bristles to sweepacross the high spots and impose excessive treatment on the latter, andinsufficient massaging action on the low spots, as would be the casewere the brush operated in a sweeping or reciprocating movement ofgreater amplitude.

As indicated, this massaging device may be hung up at a convenientposition where it will be accessible to all members of the family, forexample, each member having his own individual brush which can readilybe attached to the tang or forward end 30d of the arm 30. The devicelikewise is useful in dental offices where brushes individual toparticular patients may be provided and where brushes or applicators ofdifferent types may be employed for treating special cases.

As shown in Figs. 2 and 3, the sheath I2a of the flexible shaft I2 isprovided with a terminal portion 4l provided with an annular flange 42which seats in an annular recess 43 formed in the casing, one-half ofsuch recess being formed. in each of the sections Illa and |012. Themember 4| preferably is provided with a pin 44 which projects into anadjacent similar recess 45. A pin 46 or other stop member is provided inthe recess 45 which limits the rotation of the casing I0 with referenceto the member 4l to an angle slightly less than 360. Thus should thecasing I0 be laid upon a table or other like support while the motor isrunning, the casing and brush will not be rotated about its longitudinalaxis beyond the angle where the members 44 and 46 come intoengagementisee Fig. 5). `The mechanism within the casing may belubricated satisfactorily by placing oil or grease within thelongitudinal passage through which the shaft l5 and. arm 3|] extend. Aflexible retainer member 4l surrounding the arm 30 preferably isemployed adjacent the rear end of the guide sleeve 34 to preventmigration of grease'used for the gear 22 and pinion 23 along the arm 30.Oil or lighter grease may be provided in the chamber 48 whichconstitutes an enlargement of the axial passage 3l and within which thesleeve 34 oscillates. Oil circulation openings 49 may be provided in thesleeve and ball member, as shown in Figs. 2 and 3. Escape of thelubricant outwardly of the casing is ini hibited by the flexible member35.

While I have shown and described an embodiment of the invention for thepurpose of illustra-tion, I do not Wish to be restricted specificallythereto as various changes may be made in the details of constructionwithout departing from the spirit of the invention.

What I claim as new and desire to cover by Letters Patent is:

l. A power operated toothbrush comprising a handle constituting acasing, a brush carrying member extending into said casing, means withinsaid casing for imparting movements to said member in both transverseand longitudinal directions, a pivotal mounting for said member withinsaid casing arranged and adapted to support said member for sliding androcking movements whereby the outer end of said member is caused to movein a substantially rotary path, said movement imparting means being soarranged and said mounting being so disposed with respect to the innerand outer ends of said member as to cause the base of each bristle of abrush carried thereby to move in a substantially circular path themaximum diameter of which is being restricted within the range where thefrictional engagement of the free end of the bristle and teeth or gumswill prevent substantial relative movement thereof, whereby cleaningand' massaging action is produced by the sides rather than the free endsof the bristles.

2. A power operated toothbrush comprising a handle constituting acasing, brush operating mechanism supported within said casing andincluding an eccentric having its axis of rotation extendingtransversely of said handle and a rigid brush operating arm having asleeve operatively engaging said eccentric at one end and its forwardend disposed outwardly of said casing, a'

pvoted bearing for said arm within said handle, the throw of saideccentric being of such proportions and said bearing being so disposedwith respect to the ends of said arm as to cause the 4base of thebristles'of a brush carried thereby to move in a substantially circularpath the maximum diameter of said path being restricted within the rangewhere the frictional engagement of the free ends of the bristles withthe teeth or gums will prevent substantial relative movementtherebetween, whereby cleaning and massaging action is produced by thesides rather than the free ends of the bristles.

3. A power operated toothbrush comprising a hand manipulatable casinghaving an axial passage therethrough, a rotary driven shaft 'in saidpassage adjacent the rear end thereof, a motor, a flexible drive shaftoperable thereby and having an end disposed in said passage, meanscoupling said drive shaft to said driven shaft, a pinion on said drivenshaft, a gear meshing with said pinion for operation thereby and havingthe axis `thereof disposed transversely of said passage, a

cylindrical cam eccentrically mounted on said gear, an operable sleeveon said cam, a brush operating arm disposed in the forward portion ofsaid passage and having the forward end thereof disposed outwardly ofsaid casing, the rear end of said arm being operatively engaged by saidsleeve whereby rotary movement is imparted to said end of the arm and toand fro movement of the arm as a whole is effected during operation ofsaid gear, and a movable spherical bearing member in a forward portionof said passage through which said arm extends and oscillatable on anaxis parallel with the axis of said gear for imparting rotary movementto the outer end of said arm and an applicator carried thereby, thethrow of said eccentric being of such proportions and said bearingmember being so disposed with respect to the ends of said arm as tocause the base of the bristles of a brush carried thereby to move in anelliptical path the maximum diameter of said path being restrictedWithin the range Where the frictional engagement of the free end of thebristles with the teeth and gums will prevent substantial relativemovement thereof, whereby cleaning and massaging action is produced bythe sides rather than the free ends of thebristles of a brush.

CONRAD D. MASTRUD.

